narrated by a multitude of narrators
their numbers being such that experience / common sense rules out the possibility of their all having colluded to lie, or of their all having made the same mistake or fabrication by coincidence
with such numbers being present in each generation (level) of the chain of narration
the chain ending with something which was directly sensed (e.g. seen, heard) by the initial narrator (as opposed to something s/he concluded or hypothesized).
[see: Sharh Sharh Nukhbat al-Fikr, by `Ali al-Qari, (being a commentary on Hafiz Ibn Hajar al-`Asqalani’s summary text and commentary), pp. 161 ff.]

We encounter this type of narration often in the mundane aspects of our lives. It is by such narrations that we have come to know about distant lands which we have never visited, and similarly about events and people in the past, yet because of the certainty conveyed by these narrations, we do not doubt the existence of these entities. For example, we know about the tyranny of certain world leaders of our day, the poverty of Haiti, and the fact that there is a US-led war going on in `Iraq, because the numerous, abundant reports we have heard about these things have served to corroborate one another to the extent that we have become convinced without doubt that these are incontrovertible facts. Read more